yamdl 1.0.0

Flat-file model instances for Django

Lets you store instances of Django models as flat files (simplified fixtures). For when you want to store content in a Git repo, but still want to be able to use the normal Django ORM methods and shortcut functions.

It works by loading the data into an in-memory SQLite database on startup, and then serving queries from there. This means it adds a little time to your app’s boot, but versus static files, it still lets you write queries and have dynamic views, while all being incredibly fast as queries return in microseconds.

It does not persist changes to the models back into files - this is purely for authoring content in a text editor and using it via Django.

Why not use normal fixtures?

They’re not only a little verbose, but they need to be loaded into a non-memory database (slower) and you need lots of logic to work out if you should update or delete existing entries.

Installation

First, install the package:

pip install yamdl

Then, add it to INSTALLED_APPS:

INSTALLED_APPS = [
    ...
    'yamdl',
    ...
]

Then, add the in-memory database to DATABASES:

DATABASES = {
    ...
    'yamdl': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': 'file:yamdl-db?mode=memory&cache=shared',
    }
}

Then, add a YAMDL_DIRECTORIES setting which defines where your directories of YAML files can be found (it’s a list):

YAMDL_DIRECTORIES = [
    os.path.join(PROJECT_DIR, "content"),
]

Finally, add the database router:

DATABASE_ROUTERS = [
    "yamdl.router.YamdlRouter",
]

Usage

First, add the __yamdl__ attribute to the models you want to use static content. A model can only be static or dynamic, not both:

class MyModel(models.Model):
    ...
    __yamdl__ = True

Then, start making static files under one of the directories you listed in the YAMDL_DIRECTORIES setting above. Within one of these, make a directory with the format appname.modelname, and then YAML files ending in .yaml:

andrew-site/
    content/
        speaking.Talk/
            2017.yaml
            2016.yaml

Within those YAML files, you can define either a list of model instances, like this:

- title: 'Alabama'
  section: us-states

- title: 'Alaska'
  section: us-states
  done: 2016-11-18
  place_name: Fairbanks

- title: 'Arizona'
  section: us-states
  done: 2016-05-20
  place_name: Flagstaff

Or a single model instance at the top level, like this:

conference: DjangoCon AU
title: Horrors of Distributed Systems
when: 2017-08-04
description: Stepping through some of the myriad ways in which systems can fail that programmers don't expect, and how this hostile environment affects the design of distributed systems.
city: Melbourne
country: AU
slides_url: https://speakerdeck.com/andrewgodwin/horrors-of-distributed-systems
video_url: https://www.youtube.com/watch?v=jx1Hkxe64Xs

You can also define a Markdown document (ending in .md) below a document separator, and it will be loaded into the column called content:

date: 2022-01-18 21:00:00+00:00
image: blog/2022/241.jpg
image_expand: true
section: van-build
slug: planning-a-van
title: Planning A Van

---

What's In A Van?
----------------

So, I have decided to embark on my biggest project to date (and probably for a while, unless I finally get somewhere to build a cabin) - building myself a camper van, from scratch. Well, from an empty cargo van, anyway.

Files can be nested at any level under their model directory, so you can group the files together in directories (for example, blog posts by year) if you want.

The files are also added to the Django autoreloader, so if you are using the development server, it will reload as you edit the files (so you can see changes reflected live - they are only read on server start).